166649009 has 2 divisors, whose sum is σ = 166649010. Its totient is φ = 166649008.

The previous prime is 166649003. The next prime is 166649027. The reversal of 166649009 is 900946661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 158256400 + 8392609 = 12580^2 + 2897^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166649009 is a prime.

It is not a weakly prime, because it can be changed into another prime (166649003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83324504 + 83324505.

It is an arithmetic number, because the mean of its divisors is an integer number (83324505).

Almost surely, 2^166649009 is an apocalyptic number.

It is an amenable number.

166649009 is a deficient number, since it is larger than the sum of its proper divisors (1).

166649009 is an equidigital number, since it uses as much as digits as its factorization.

166649009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69984, while the sum is 41.

The square root of 166649009 is about 12909.2605907542. The cubic root of 166649009 is about 550.3017726858.

The spelling of 166649009 in words is "one hundred sixty-six million, six hundred forty-nine thousand, nine".